package com.jicheng.filter;

import com.alibaba.fastjson.JSONObject;
import com.jicheng.Utils.HttpRequestUtil;
import com.jicheng.Utils.RedisUtils;
import com.jicheng.Utils.SpringUtils;
import com.jicheng.config.shiro.JWTToken;
import com.jicheng.constants.Constants;
import com.jicheng.controller.LoginController;
import com.jicheng.ext.response.ErrResponse;
import com.jicheng.ext.util.HttpClientManager;
import org.apache.shiro.authc.AuthenticationException;
import org.apache.shiro.authz.UnauthorizedException;
import org.apache.shiro.web.filter.authc.BasicHttpAuthenticationFilter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.HttpStatus;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.URLEncoder;

@Component
public class JWTFilter extends BasicHttpAuthenticationFilter {
    private Logger logger = LoggerFactory.getLogger(this.getClass());


    /**
     * 如果带有 token，则对 token 进行检查，否则直接通过
     */
    @Override
    protected boolean isAccessAllowed(ServletRequest request, ServletResponse response, Object mappedValue) throws UnauthorizedException, AuthenticationException {
        RedisUtils redisUtils = (RedisUtils) SpringUtils.getBean("redisUtils");
        //判断请求的请求头是否带上 "Token"
        if (isLoginAttempt(request, response)) {
            HttpServletRequest req = (HttpServletRequest) request;
            String tokenkey = req.getHeader("Token");
//            //查询黑名单，如果存在则让重新登录
            String tokenValue = (String) redisUtils.get(tokenkey);
            try {
                if (tokenValue != null) {
                    throw new AuthenticationException(Constants.TOKEN_FAILURE);
                }
//                //如果不存在黑名单，则进入 executeLogin 方法执行登入，检查 token 是否正确
                executeLogin(request, response);
                return true;
            } catch (Exception e) {
                //token 错误
                responseError(response, e.getMessage());
                return false;

            }
        }
        //如果请求头不存在 Token，则可能是执行登陆操作或者是游客状态访问，无需检查 token，直接返回 true
        return true;
    }

    /**
     * 判断用户是否想要登入。
     * 检测 header 里面是否包含 Token 字段
     */
    @Override
    protected boolean isLoginAttempt(ServletRequest request, ServletResponse response) {
        HttpServletRequest req = (HttpServletRequest) request;
        String token = req.getHeader("Token");
        return token != null;
    }

    /**
     * 执行登陆操作
     */
    @Override
    protected boolean executeLogin(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        String token = httpServletRequest.getHeader("Token");
        JWTToken jwtToken = new JWTToken(token);
        // 提交给realm进行登入，如果错误他会抛出异常并被捕获
        getSubject(request, response).login(jwtToken);
        // 如果没有抛出异常则代表登入成功，返回true
        return true;
    }

    /**
     * 对跨域提供支持
     */
    @Override
    protected boolean preHandle(ServletRequest request, ServletResponse response) throws Exception {
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        httpServletResponse.setHeader("Access-control-Allow-Origin", httpServletRequest.getHeader("Origin"));
        httpServletResponse.setHeader("Access-Control-Allow-Methods", "GET,POST,OPTIONS,PUT,DELETE");
        httpServletResponse.setHeader("Access-Control-Allow-Headers", httpServletRequest.getHeader("Access-Control-Request-Headers"));
        // 跨域时会首先发送一个option请求，这里我们给option请求直接返回正常状态
        if (httpServletRequest.getMethod().equals(RequestMethod.OPTIONS.name())) {
            httpServletResponse.setStatus(HttpStatus.OK.value());
            return false;
        }
        return super.preHandle(request, response);
    }

    /**
     * 将非法请求
     */
    private void responseError(ServletResponse response, String message) {

        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        //设置编码，否则中文字符在重定向时会变为空字符串
//            message = URLEncoder.encode(message, "UTF-8");
//        try {
//
//        } catch (IOException e) {
//            e.printStackTrace();
//        }
//            throw new AuthenticationException(Constants.TOKEN_FAILURE);
        try {

            JSONObject result = new JSONObject();
            result.put("code", false);
            result.put("message", message);
            result.put("data",null);
            this.writeJson(httpServletResponse, result);
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

    private void writeJson(HttpServletResponse response, JSONObject json) {
        ServletOutputStream out = null;
        byte[] bytes = json.toJSONString().getBytes();
        try {
            //设定类容为json的格式
            response.setContentType("application/json;charset=UTF-8");
            out = response.getOutputStream();
            //写到客户端
            out.write(bytes);
            out.flush();
            out.close();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
//            if (out != null) {
//                out.close();
//            }
        }
    }
}
